In recent years, thin emissive type image display devices have been drawing attention as image display devices replacing LCDs. Examples of the emissive type image display devices include plasma display panels (PDP), flat panel displays using an electron source of such cold cathodes as field emission type electron-emitting devices (FE) or surface conduction type electron-emitting devices and effecting light emission by irradiating phosphors with electrons emitted from the electron-emitting devices, and so on.
In the display devices using the cold cathodes such as the above FE and surface conduction type electron-emitting devices, the principle of light emission is basically the same as that of cathode-ray tubes. For that reason, they have the potential of achieving the luminance and contrast basically equivalent to those of the cathode-ray tubes.
The image display devices using the surface conduction type electron-emitting devices are disclosed, for example, in Japanese Patent Applications Laid-Open Nos. 6-342636, 7-235256, 8-007745, 8-034110, 8-045448, 8-171850, 8-236017, 9-069334, 9-102271, 9-106755, 9-129119, 9-129121, 9-129125, 9-138509, 9-161666, 9-245690, 9-259741, 9-259742, 9-283012, 9-283013, 9-306359, 10-021822, 10-021823, 10-050207, 10-050209, 10-144204, and so on.
FIG. 9 and FIG. 10 show the schematic structure of an example of the surface conduction type electron-emitting devices disclosed in the above applications. FIG. 11 shows a schematic, structural diagram of an example of the image display apparatus using the surface conduction type electron-emitting devices, disclosed in the above applications.
FIG. 9 is a plan view of the surface conduction type electron-emitting device and FIG. 10 a cross-sectional view of the surface conduction type electron-emitting device. In FIG. 9 and FIG. 10, numeral 101 designates an insulating substrate, 104 an electroconductive film, 102 and 103 electrodes, and 105 an electron-emitting region. The electron-emitting region 105 has a gap. When a voltage is applied between the electrodes 102, 103, electrons are emitted from the electron-emitting region 105.
In FIG. 11, numeral 108 designates a rear plate, 109 an outer frame, and 110 a face plate. Joint parts of the outer frame 109, rear plate 108, and face plate 110 are sealed with an adhesive of low melting glass frit or the like not illustrated, thereby composing an envelope (airtight vessel) for maintaining the inside of the image display device in vacuum. The substrate 101 is fixed to the rear plate 108. The surface conduction type electron-emitting devices 113 are arrayed in the matrix of N×M on the substrate 101 (where N and M are positive integers not less than two and properly set according to the number of pixels in an objective display image). The phosphors are arranged opposite to the respective electron-emitting devices.
The electron-emitting devices 113 are wired in the matrix with M column-directional wires 107 and N row-directional wires 106, as illustrated in FIG. 11. Unrepresented insulating layers for electrically insulating the wires from each other are formed at least at intersecting portions between the row-directional wires and the column-directional wires.
A fluorescent film 111 consisting of the phosphors is formed on a lower surface of the face plate 110. A metal back 112 of Al or the like is formed on a surface of the fluorescent film 111 opposite to the rear plate 108.
In the case of color display, the phosphors (not illustrated) of the three primary colors of red (R), green (G), and blue (B) are separately laid. A black material (not illustrated) is laid between the above phosphors of the respective colors forming the fluorescent film 111.
The inside of the above envelope (airtight vessel) is maintained in the vacuum of pressure lower than 10−4 Pa. In this way, the clearance is normally kept in the distance of several hundred μm to several mm between the substrate 101 with the electron-emitting devices formed thereon and the face plate 110 with the fluorescent film formed thereon.
In a driving method of the image display device described above, a voltage is applied to each electron-emitting device 113 through external terminals Dx1 to Dxm, Dy1 to Dyn and through the wires 106 and 107, whereupon each device 113 emits electrons. At the same time as it, a high voltage of several hundred V to several kV is applied through an external terminal Hv to the metal back 112. This causes the electrons emitted from each device 113 to be accelerated and collide with each corresponding color phosphor. The electrons excite the phosphors to induce emission of light, whereby an image is displayed.